Control apparatus



Aug. 20, 1963 R. E. MICHEL CONTROL APPARATUS Filed Nov. 21, 1961 m m E DI N o O w 3 A R o* om .5.85m .EEE oo.

ATTORNEY.

' algas Iof a given mass.

3,100,963 l CN'IRGL APPARATUS y MicheLfGolden Valley, Minna,V assignmtoMinneapolis-Honeywell Regulator Company, li/Iiiunfe-A apolis, Minn., acorporationoi Delaware Filed Nov. 21, 1961, Ser. No; 153,866

" Claims. (Cheli-$5.6)

Raymond E.

' "I'hisinvention relatesv to lreaction control systems and moreparticularly ,to digital reaction controlsystems. Areaction" controlsystemis the -genericterm applied to a control system utilizedv invarious-,applications-includmg space vehicle stabilization"andlattitudecontrol Vin vwhich l a `force utilizedto control thevehicleisjalreaction `force that.` follows Newtons Third Law.=of\-Mo-tion.5..The re,

chemicals, -rather'than normal combustion, to

A l 3,100,963 Patented Aug. 2o, 1963 generate thegases. Thus, the rapidgeneration of the gases by the` detonation, which tak-es place ina fewmicroseconds,` eliminates --th'e slow pressure or impulse rise timeinherent ina normal combustion process. Y Inaddition, 'the utiliza;-

'tion ofa detonation allows the lelimination of the normal i kthe longimpulse decay time..`

lactionforce may be obtained through the utilization of `inertia 'wheelsor inertia spheres; acceleration or decelera#- Ition of the wheels orspheres results in a reaction force being; applied to the vehicle.In'addition, it is possible v Vtofuse ihot gas .controls ori. cold gascontrols in which a `working gas is contained within lachamber withinthe veliiclelk HA reactionvforce is applied Vto the vehicle in Vresponseto the dissipation of the gas from the vehicle;

the force is produced -by the reactionto the acceleration of It is Ialsopossible. to use hypergolic controls in which a gas is .generated withinya chamber within a vehicle through the Vutilization of .hypergolicchemicals. A hypergolic chemical is dened as a chemical which is capableof self-ignition upon contact withf another chemical. It should be notedthat a hypergolic chemical `is notcapable of self-ignition upon contactwith any other chemical; but rather is capable of "self ignition onlyupon Contact with certain other chemicals.

Inpractice, la plurality of suitable hypergolic chemicals are chosensothat `a `combustion or detonation occurs and a `gas is generated, whenthe chemicals are brought into contact in a particular manner in a:suitable chamber.

A reaction force -israpplied to the vehicle in response to` thedissipation of the gas fltmfl. the vehicle; the force is y l reduced`bythe. reaction ,of the acceleration 'of a gas of a' given mass.`

This `invention relates to digital hypergolic'reaction control systemswhichVutil-ize a* plurality `of hypergolic chemicals,`which :possesstheproperty of igniting upon contact withv one another, to" generatealgas which is"V expelled from the vehicle so as tto obtain areactionforce which `is` utilized to control the vehicle.` In theapplicants inventiomthe gas isalternately generated. within f `andexpelled from a suitable chamber Whichresults in a d plurality/,offorces or'ir'npulses, equalin magnitude and I sulting .in anotherdetonation.

combustion chamber which results in the .The applicants' unique systemalso utilizes the pressure developed by the detonation to control theoutputof the j; fig system .therebyjreducing the value` actuationlagsand f providing a square wave,fshort pulse Width, impulseor output.V TheOutput is controlled by con-trolling thefad-Vv mission of hypergolicchemicals to a` detonationchamber.` During a detonation, admission ofthe hypergolic. chemicals to the detonation chamber is prevented. .Im-

mediately upon. completion of the detonation, ithepres-.j sureisdissipated out to the detonation chamber resulting in an .impulsebeing applied to the vehicle. lW-hen. the

chamber pressure is reduced, additional hypergolicchemi-v apparent froma study of the accompanying specification and` claims in conjunctionwith the'drawing in [which:

FIGURE 1 is ya somewhat schematic cross vsectional view `of a prior artdigital hypergolic reaction control jet;

FIGURE @2 is a somewhat schematic cross sectional view of one embodimentof theapplicantsl invention;

FIGURE 3 is a schematic [available froml a prior ar-t device and frominvention; and

FIGURES :is a schematic cross sectionaliviewv ofrthe tapplicantsinvention.

Referring now .to `FIGURE 1 generally depictsa digital hypergolicreaction control l yietf-,of a conventional. or pri-or, art' design. -Itshould be understood that the digital hypergolic reaction controlr jetillustrated in FIGURE l'Y is .normally rutilized` in af reaction controlsystem., There may beas manyaseight `V such jets,V all identical,controlling vthe attitude .of'fa" spaice equally. spaced in time,`beingepplied to the vehicle.

'I'hese pulsating -fonces for impulses identify the hypergolicreactioncontrol systemasfa digitalrcontrol system.`

V,iHeretofore,. digital hypergolic reaction control'systems havenotprovided the desired square wave, short. jpulse'` width,- outputorir'nl'mlses.V .Thefsquare wave,

short pulse Width, impulses have not been obtainable.

dueto the valve actuationlagsand ignitionlags inherent in the earlierdesigns.` Generally, solenoid controllersare utilized in `priorartfdesigns for valve actuation which necessarily .limits -thefvalveactuation times to valuesV greater "than desirable. In addition, thenormal combustionprcess which occurs in `iaconibustio-n chamber'in aprior art system results'in a gradual gas pressure or impulse rise timeof `a few milliseconds. Further, the combustion chamber required resultsin a long pressure or impulse decay time of ,a few milliseconds.

The applicant has eliminated the inherent disadvantages A 'generallycylindrically shaped combustion chamber hriusingfl'l` defines acylindrically shaped combustion chamber 1 2.` One end of the cylindricalcombustion rchamber- 12Y isV closed by a valve housing 13..which issecurely attached toV chamber housing L11. A reactionA nozzle 14,generally shaped in the form of a diverging cone,.is attached rto theother end of the combustion 12- andfunctions to direct the gases fromcombustion cham'- ber "12. Two valve: elements 15 and'16 areV positionedwithin valve chaunbers 17 and v18 located within valve housingrl. Thevalve elements 15 and'16 seat against valvel seats 19 and 20respectively.. The valve chambers 16 and v17 communicate with combustionchamber l12' through passages 21 and 22 respectively. A supply line 25communicates with valve chamber 17 and supplies a suitable hypergolicchemical (such as unsymmetrical diof the prior :art digital hypergolicreaction control systems and provides a square wave, shortpulse Width,impulse through the utilizationof a unique system. Tiheiapplif cants`unique system `utilizes a detonation of 'hypergolic methyl hydrazine('UDMH) which is normally referredrto by those skilled in the art as Lafuel). A` supply line Z6 communicates with valve chamber 18 and suppliesa suitable hypergolic chemical (such as nitrogen-tetroxide which isreferred to by those skilled in the art as an elimination of` diagram'of a digital controller; l

FIGURE 4 is a chart indicating Ithe relative outputs.

the applicants reference numeral 10 Y.

` cylindrical mount.

' oxidizer). The valve elements-15 and16 are biased in the closedposition, against `valve seats V19 and' 2.0i, by

Vvalve springs 27 and 28. t

Aseieneid su is provided which is attached to the valve housing 13lbysuitable means such as a threaded The solenoid 30 comprises a cylin-ldrical armature member-31 land :a .winding means 32.

chamber 51. Control means65 yand control means 75 are y identical.Control means-65 comprises'two'valve means f Y 66 and 76, and controlmeans 75 comprises two valve j' means 86 and 87. Valve means 66 and 86are identical f andvalve means 76 and 87 are identical. Consequently tthe detailed description of the ycontrol means will be The armaturemember 3'1fhas an Velongated eXtension por-v Y rtion 33 which extendsalong the .axis of the armature 31,'

towards the valve housing 13.V Two rocker arms 34 t and 35 arepositioned between the end Vofzextension lpore tion'33 of armature 311and the valve elements 15 and 16 t respectively. The rocker arms 34Y:and 35 are piyoted. at Y pivots 36 Vand 37 Yso that movement ofextension portiony 33 of armature. 31, to the leftgxas viewedin FIGURE-l,

' willy withdraw the valve elements 15.1and 1 6 from lthe .valve fseatsl19and2tke r `ln operation,A the solenoid through leads '38 fandconnector 39 Ifrom a suitable digital l. controller, (not shown). vEachenergization of lsolenoid windings .321 causesarmature memberV 31` andarmature yextension 33 to be displaced to theleit'as vviewed in` FIGUREl. Displacement of armature 371and exten- 1 sion portion 33 to the leftcauses rocker arms34 and'SS topivot about pivot points36 and 37 and4vvithdrawfvalve elements. '15v and 16 from the valve seats 19 and 20.

Thisallows fuel from supply line 25'and 'oxidizer .from

supply line 26 to flow through valve chambers 17 and 18 and passages 21and 22 and enter thecombusnon chamber 12.` Since the fuel and theoxidizer are hyper? golic chemicals, they ignite upon contact and normalcombustion takes place within combustion chamber 12.

within the chamber. The pressure yis Vgradually dissipated outcf .thereaction nozzle. 14 which results in animpulse being applied to thedevice' 10 digital toward the right as viewedV in FIGURE l in accordanceWith'gliewtons Third Law of Motion. x The impulse `generated by thereaction jetis characterized by a relatively long rise time and arelatively. long decaytime which resultsV in a pulse width 'ofyconsiderable magnitude.

Referring now tov FIGUREZ, reference numeral 5t) .generally depicts oneembodiment of theapplicants unique digital hypergolicmeaction controlsystem. A

l small cup-shaped detonati-on chamber 51 is provided-with- Ain lavcontrol means housing 52. VA `diverging cone or reaction nozzle'57 ispositioned .at the open end ofl com'- bus'tion chamberSl and is rigidlyattached to the control i means housing 52 vby suitable means k(notshown). It

windings `:32.* are energized limited to the description ofcontrol'means V65'.l The Vdetailed description of control means 65 willYbe limited to the description of valve means 66 and 76. c Y Valve meansy66 comprises a pressure responsive element 67, which may take the",form of a reed as'illustrated in 1 FlGU-RE 2, The pressure responsiveelement 6t7`is attached toA housing 52 as" at pointf'S. The pressure,re-'' sponsive element 67 assumes an open position when valve" 76 is inthe closed position, as'illustrated'in-FIGURE2. The pressures oneitherside of element 67 are substantially t equal, however functionallyvalve 166 may be considered-as v the closed position4 when the pressurein valve chamberfj4 5'5 exceedsthe supply pressure in supply pressure665] Valve means 66 is generally referred to as a ilapper; valve, checkvalve, or reed valve by those skilled iny ther-art. 1 ItV y t should benoted' that .valve means 66vmay-jtakefther e structural forms and theapplicantdoes notwi'sh toV be '.Normfa-l combustion is dened asasubsonic combustion. The normal combustion generates gases w1th1ncombustion chamber 12 and results in a subsonic pressure builduplopen.,l Pressure responsive element 67 will be yforced'to limited to theembodiment illustrated in FIGURE 2Q 'For example, Vthis type of valvemay be .of the rotary type, 'and' controlled electricallyor mechanicallyinstead of by presx sure. In one embodiment oflthis type of valve, the`valve t would be operable in response to a control signal so that itwould be closed during the'fperiod of increased pressure in chamber 55and open when .-valve 76 is open. i

A sensing means 69 is provided :contiguous valve cham- (ber 55.- Whenthe pressure within valve chamber 55y exceeds a critical value sensingmeans Y69 produces a feed` back signal indicative thereof. VOnefmeanso'faccomplishing this'result isillustrated in FIGURE'Z- iriwvhich Y sensingmeans` A69 comprises a precision plunger actuated switch or othersensitive means which provides an elec f trical signal when apressureisexerted thereonpWhen pressure responsive -elem'ent1t7` is forced intocontact with' v sensing means 69'ulpon an increase in pressure invalveVV will be noted that the detonationfchamberlSl in the emi.

bodiment illustrated, isextrernely small in size, and is so lshaped .tobring-the propellants together atan interface in l chamber 51 to cause adetonation wave combustion. The utilization of a detonationchamberofditferent shape and size islwithin the scope of the inventionandthe applicantycloes not wish to be limited to the shapeandsizeindicated in the .embodimentdisclosed j On thefclosed end ofl detonationchamberSl'ports 53 and 54 are provided. Port 53 communicateswitha valvechamber '55 locatedwithin housing 52. P=ortj54communicates with a valvechamber 56 located withiny housing' 52. A supply v n passage 60 isprovidedv which communicates with-valve Achamber 55.n Supply passage 60supplies, under -aV pressure of 50 to 150` p.s.i., a suitable hypericalchemical, such as hydrazine ,which is generally referred 'toby thoseskilled in the art as a fuel. A supply passage 61 is provided whichcommunicates with valve chamber 56 and i Y supplies,-under a pressure of50 to 150 p.s.i., a suitable hypelrgolic chemical such asnitrogentctroxidc, generally referredlto by vthose skilled in the art.as an oxidizer.

vControl means `65l and 75 are positioned with valve chambers and 56respectively yand function yto control the supply of hypergolicchemicals to thc detonation winding means 31..

chamber 55', acsignal is provided indicative thereof.

Valve means 76 comprises a control valve mea-nscapfl` able of allowingorY preventing'iovv of a hypergelifchem cal therethrough in response toacontrol signal. Avnumber' of variousvalve conliguratio'ns will performthis'iunction.

Y `Onesuita-ble type is the solenoid actuated valve 'illustrati-idfV inFIGURE` 2. In FIGURE 2, control yvalve means 76",'V

'comprises Yvalve element '/Tvvhich cooperates with valve yseat 78located Within valve chamber 55.* [Valve elementvv 77jis normally'biasedagainst valve seat 81by means of`v valve spring 9,.;vAnarrnatur'eelement @itis attached to they efnd of valve element '77and cooperatesY withv solenoid` YEn'engization ofi solenoid winding"Vmeans 811 bya controlusignal resultsin armature element 80 l and valveelement 77 vbeing displaced away from valve seat y l 7 8` thus openingthe 1Y valve' f means .76.13 j;

Adi tal controller 71 is provided `toconver''tjfan"input'.V

signal from anl attitude sensor tof asuitable control sign through lead92. Counter 91 is also connected to leads 7d and 72. Theoperation ofthe'ldigital controller 71 will be more fully 'discussed hereinafter.

Operation v rIn operation, the unique hypergolie reaction lcontrolsystem functions as followszan analog input signal is con- 5 ducted froma suitable attitude sensing means, such as a gyroscope, through lead 73.This input signal isconducted to analog to -digital converter 90* IWhichconverts. the input signal to a digital signal, that is, a specificnumber of pulses. .The digital signal (pulses) is conducted through lead92 to counter 91 which counts up the numberv ofi is a series ofimpulses. The number of impulses generated is indicated bythe'vfeedbaclcpulse fromfthe sensing g means 69 to the digital `controller71.v The digital conpulses. When counter 9"1,counts the first pulse, acontrol .Y

signalis conducted through lead 72 to Winding means S1 of control-valve76. Energization of the solenoid winding 811 causes the `valve `element77 to be Withdrawn from the valve seat 7 8 by overcoming the-force of`the biasingspring 79. Since the valveunea'iis366` isnrmaIlyKopenQahypergoliclchemical ilovvsV frorn'fs'upply passage ,'60 through valves*66 and 76,valve chamber S'Siand port 53 and enters" detonatiou chamber51al The control signal lead '72 also enengizes valve means 87 ofcontrol means 75 sothaty a` hypengolic chemical is 'also-supplied tothedetonation chamber 51 from supplypassage 61.

' When the hypengoli-c chemicals come into detonation v, chamber 51 theyare combined so that a detonation'is'proJ duced and gases aregenerated'therein. VThis requires that the hypergolic chemicals beparted into the detonation chamber; so that an interfacefis createdtherebetween. Also, the dimensions `of thevdetonation chamberv 51v arecritical and must be chosenaccording to the amount fof hypergolicVchemicals introduced Itherein.` A detonationv is deiined as a`supersonic combustion. The detonation will take place rin approximately10i to 20 microseconds and therefore, detonation is `complete beforethegases are dissipated from the `detonation chamber 51 through nozzle57.

Consequently, the pressure Within detonation chamber v '51 rises to avery high level, in the.l5,000f to the 30,000 pound'per square inchrange.

the pressure Within the valve chamber 55 to a Value great- Thismomentarily raises er than the pressure in supply passage 60 (SOLlSOiVp\.s.=i.')l.`

Since valve means 76 is open; this increased [pressure causes pressureresponsive element `67 to be -fonced to the closed position therebypreventing the hypengolic chemical ,in supply-passage -60i from beirigvforced upstream beyond pressure responsive `element "67. Should thechemical be forcedV upstream, there would be an undesirable time lagbeforeit-Would `flow lb ackjtothe chamber. Itshoulid be' noted that theincrease in pressurey due tothe detonation prevents the hypergoliochemical .from entering the lchambei'.` The valve 66prevents the Vtransmission of the presvent the hypergolicchemical insupiply line 6lfrom being" Y foncedupstream beyond element86ffWhenvalvegmeansy66"istforced toy theclosed position, sensing means 69' surefrom thechamber 51 to the passage 60. Valve lmeans v 86 of Acontrol means# 5yoperatesinma similar manner to pre-v Aceivedby' `the.counter`91 a'control''sign-al' isconducted, Vthrough lead 72'tothe controlv'alvrneans76.' v AI n addi-` tion, theicounter counts up thelO'pulsesconducted from the converter. After the Vdetonatiorr takesplace and the' troller 712 compares the feedback signal with thev inputsignal toV determinetheytota-l number Vof impulses required to producethe necessary total impulse to reorient thespaQevehicIe in accor-dancewith the input signal. Y' Takingya specific example, suppose that theanalog k'to digital'converter 90 will convert theaualog input`-sigrial`intothe correct'riumbe'r ofx pulses, 10, in this example.

The pulses are conducted `from the converter 90 through lead92jtof`thec`ounter 91." When the firstpulse is repressure l responsivevalve 66 'isfforced closed,- sensing y means- 69 generates a feedback'pulse through lead 70 lto l,

the counter 91. This feedback pulsefis'counteddown on' the counter 91.`Therefor'eynine, pulses are now indicatedon the counter 91. After Vninemore deton-atiorrsf` and nine `morefeedback pulses thejcounter willshowV zero pulses and the control ysignal will be terminated.

" Upon termination of the controlsignal, control valve,

meansj76 is forced to the closed position by valve spring 77; Controlvalve means 87 is closed in ja similar manner.' Therefore, no hypergolicchemical enters detonation chamber57 and no output is obtained from thesystem, i,

The impulse characteristic yof the applicants unique hypergolic reactioncontrol system is illustrated in the Impulse Characteristic Chart inFIGUREV 4. The ordinateof thechart is thrust percent and the Vabcissa istime in milliseconds.

golic reaction control systems dueto thecombustion lags,combustionchamber characteristics, andthe valve actuation lags'.`Consequently,"'the` Iapplicant obtains van impulse characterized by arelativelylsho'rt rise time and a relatively short decay time. Statedotherwise, the applicant obtains a squarefwave,`fshort. pulse Width,impulse. The impulse that is obtained by the applicants unique design'is identified 'in IFIGURE 4 by theterm detonation` impulse. The impulsethat is obtained with the priorart'devicetsuch as illustratedvin FIGUREl) is generates a feed-back signal (pulsef),V through leadf7tl= tov,

@the counterylsiofuigaal controller '71; The aanpak vpulse. counts downon the'counter 91. l. i

Iinmediatelyfafter `the pressure' increase dueVV to the detonation, thepressure in'detonation chamber 5-11i`sf dissipated throughreactionnozzle"57, and results-iijanim'- pulse 'being applied to thefhousing 52 andthe lspacevel resultsina'piulse width' of considerablemagnitude. Itl should be lnoted that the pulse width of the detonation'l offclarity.v Actually the pulse width is onlyf1020 microfsecondsff Acomparison ofthe relative pulse vWidths illus-l on of Ithe gradual risetime and'gradual,n

bicle. As` 'the pressure in detonationk chamberSlfisV reduced, thepressure in valve chamber V,55,1 is reducedto a value less than thesupplypressure and pressure re'sponl4 sive valve `66is forced open.-"Agaiir'a hypergolicpchemi` cal flows from supply passagethroughvalves'66.and`v 76 and enters detonationcharnber 51. [Ahypiergolic chemical alsofenters detonation chamber 51 from supply'passage 61.` -Again a detonation resulta-'raising the pres! sure of thedetonationrchamber V51. and valve chamber 55 and 56 forcing valve meansV66 and 865m the closed position.` "Another feedback pulse is conductedfrom the sensing means 69 t'ocounter 91k and another impulse is appliedto the spacevehicle; If another type of valve is utilized, for exampleVa rotary valve, a control signal willlbe utilized to operate the rotaryvalve. Y The rot-ary vvalve may be designed so as to be operable inresponse ltrates the eliminati superimposed upon the Vgraph 'iuFIGURE 4and is identi'ed bythe vterm ipr-i-orart impulse. Theprior artdevicesfpbtam lan impulse f characterized by .a relatively longvrise`tirrieandA a relatively long decay time; This impulse isgreatlyexaggerated in FIGURE 4 forlthe sake Adecay time by the applicantsinvention.

is rdefined asI the ratio lof the pounds thrust developed per pound ofpropellant liow.` The vast reduction `in the length .of the detonationchamber asV compared to theto theinput signal which controls controlvalves 76 and Thus the output of the digital reactioncontrol system( Theapplicants `unique design elimif nates the mhereutV time Ilags oftheprior art digital hyper-y The applicants unique systemhasfthe'advantageoverr thejplrlor' art devices of retaining av highspeciicimpulse f V'vt/lille `generating a minimumimpulse.Q'Specifiz,impulse ,l

Y 1 Vfrom the'spirit and the'scope of this-invention.v

.1i-1 produce saidcon'trol signal.A

like components; The yembodiment of 'FIGURE 5 is l similar totheembodiment of FIGURE 2 with the exception that the valves-66and 86 IareVpositioned intermediatethe-controlvalyes 76 and 87 and the detonationchamber' 51. L `In allrother structural details thev embodimentillustratedin'FIGURE 5j is identical to vthe embodiment illusillustratea'll'of the components. It will be 'understood URE 2. Consequently,y nofurther discussiomis"deemed in F-iGURE f5 is that'wlien the controlvalyesare shut 'off all ther hypergQl-icgchemical on the detonationcharn-` i rber side 0f the'con'tr'o'l rvalve is lostl from yfthevsystem` since Vth'epressure responsive'valves are normally open.'

'-,tratefd iiiFIGURE 2 and itu/as not deemed ,necessary to l Y sure insaid chamberpsaid pressure responsive valve means being closed inresponseto the increase in ,pressure thereby preventing the pressureincrease from being Ytransmitted to said passages and preventing-saidfuel and sai-d oxidizer fromyentering saidl chamber, the pressure beingdissipated fromsaid `chamber through said nozzle resulting in `a forcebeing applied to said housing,

A' reduction of vthe pressure allowing-,said pressure responthat `the*embodiment illustrated [in FIGURE 5 operates v in a manner similar tothe embodiment illustratedin FIG- sive valve means to open and toalloWjsaid fuel and said oxidizer to enter said chamber Vtherebyproducing a-second detonation; sensing means for producing a feedback`Vsignal indicative of the number of detonations; and means` icornbining'an inputfsignaland'jsaid :feedback signal so vas to produce saidcontrolfsignal." Y ,v n Y y 3. in a digital reactioncontrol systenuahousingglaf detonation chamber within saidghousing;` a nozzle con-knected to' said chamber; a passagesupplying a lirsthyper- Vgolicchemical to said'chamber; a passage supplying a second hypergolicchemical to said chamber; means conl. n

trollingthe supply of said first and said second chemical.

While I have shown and described specific embodiments Y ofthis'invention, vfurther modiiication and improvementsl Will'occur vto4those skilledin :the art. 'I'des'ireit'to'be ,understood therefore,ythat Ythis invention is not limited to the particular lform shown and-I intend in the appendedl claims to cover all 'modifications which do'not yI claimas'tmy invention; y v

1.In a digital reaction control,V system: a housing;

afdetonation chamberwithin said housing; a reactiony depart f i to saidchamber, said means comprising rst valve means l and second' valve meansvpositioned Within each of said passageafsaid rst valve' means normallyVbeing closed and said-second valve means normally being open, saidfirst valvemeans vbeing opened in response to a control v signal so asto permit said first and said secondchemical to enter said chamberthereby producing a detonationY g and generatingjgases therein,saidasecond valve means beingclosed in response to said detonationthereby preventing said -lirst and said second chemical'from enter- Ying said chamber, said gases being dissipated through nozzle connectedtosaid chamber; a passage supplying a Vfirst hypergolic chemical to saidchamber; apassagesupplying a secondhypergolic,chemical to said chamberymean rcontrollingsthesupply of said irstand saidzsecondy chemicaltofsaidlchamber, said'means comprising conf trol Valvewineans andpressure ,responsive valve. meansv Y `positioned within each of saidpassageasaid controlV vvalvemean'sv normally/being closed and, Vsaidpressure` responsive valve means normally being open whereby said 'rstand'salid second chemical are prevented from entering-said chamber, saidcontrolgvalve means beingr Y opened-in responsev to aicontrolsignal' so.as to allow said fiirst'and said second chemicaltoo-enterr said chambertherebyproducing-a jdctonationi-whichresults in an in,-V

creasey in pressure in said.chamljier;` the'increase in pressurepreventing said `irstiand said secondchemicals from ventering saidchamber',;said pressure responsive rvalve meansbeihgclosed inlresponsetothe pressure increase a thereby preventing the pressure increase frombeing trans-;

mittedfrvom, said chamber to:saidjpassages, the pressure beingdissipatedthr'ough saidgnozzle resulting in afiforce vbeingapplied tosaid 'housing'jreduction ofsaid chamber l pressureallovving saidpressure responsive -valrvesmeans to open.andjtloallowv said iirst andsaid` second chemicals I to'entersaidhchamberthereby producingaseconddetonasaidjnozzle and resulting in an impulse beingappliedj to lsaidhousing, the dissipation of said lgases permitting said first valvemeansto open permittingsaid iirstV and said second chemical to enter saidchamber thereby producing f a'second detonation; sensing means `forproducinga feedtion; sensing Vine-ans for 'producing a feedbacksignalin- .dicative off th'epumber vofk detonations; and meansf com- 'vVbining an` input" signal and said -feedbackfsignal lso as tok 2. kInadigitalV reaction control system: a housinggfa detoiiation chamberWithin said housing;r areaction nozzle V connectedtofsaid chamber; apassagesupplying hyper-A -golie f uel to said chamber; a passagesupplying hypergolic voxidizer to said chamber; 'means controlling vthelsupply of said fuel and said oxidizer to said chamber, said meanscomprising control valve means'and pressurevrel spoiisive lvalveV meanslpositioned within each of said passages,` said'control valveV meansnormally being closed f' and said pressure responsive valve meansnormally being operiu whereby said yfuel and said oxidizer are preventedfrom enteringt said chamber, said control valve means being openedinresponse tov acontrol signal so as to allow said fuel and said oxidizerto enter said chamber thereby producing a..detonation and increasing thepres- `back signal indicative of the number of detonations; and

means lcombining an input signaland said feedback sigf nal so as toproduce said control signal. g

l4. ln a digital control system: ahousing; a detonationchamber Within'said housing; a passage supplying a iirstr chemical to said chamber; apassage supplying a'secondf chemical to said chamber; means controllingthesupply of said'iirstand saidY second chemicals to saidjch'amber," ysaid means comprising first valve means and Vsecond Vvalve Q meanspositioned Within'each of said passages, said ffirst valve meansnormally being closed and said second :valve means normally being open,said first valve, means being opened in response to v'a'control 'signalthereupon permitting said first-y and Ysaidsecond chemical to enter saidchamber and-,detonateproducing gases'thereim said sec-lond yvalve meansbeing lclosed in response'to the detoiia- V tion thereby preventing saidiirst and said secondSchemi-A cal from enteringV said chanibemsaid.gases-being dis-,v

sipated'from said chamberdresulting l in an impulse being. fappliedvltojsaid housing, sensing means forproducin'gla Ifeedback`signal of the number of detonations; and means, Y combining an-inputsignal and said feedbacksignal so as y to'produce said control signal. ic 5.In adigital control system;l a deton-ation chamber;

a passage supplyinga `firstlhypergolic chemical torsaid chambenapassagesupplying a'second hypergolic chemi- Y v cal yto said chamber;control valve means and pressure responsivexvalve means positionedwithin each of said passages, said control valve means normally lbeinlgclosed l and pressure responsiveivalvemeans normally being open,ysaidcontrol Valve means being opened in response toa control signal soas to permit said iir'st andsaid second chemical to enter said chamberthereby producing la detonation, said pressure responsive valve meansbeing closed in response to said detonation thereby preventing saidiirst and said second chemicals from entering said chamber,

gases produced by said detonation being dissipated froml said chamberresultingin an impulse fbeing applied to said chamber, sensingme-ans forproducing a feedback signal indicative of the number of detonations; andmeans comf valve means normally bein-g closed and said second valvemeans normally being open, said rst valve means being operable inresponse to a control signal so as to permit v said rst and said secondchemical to enter said chamber thereby producing a ldetonation andgenenating gases lsherein, said second valve means being closed duningsaid detonation thereby preventing said iirstrand said second chemicalsfrom entering said chamber, said lgases being dissipated fromsaidchamber resulting in an impulse being applied to saidVch-amber, sensingmeans for producing a Ifeedback signal indicative of the number ofdetonations; andmeans combining an input signal-and said Afeed-backsignal so as to produce s-aid vcontrol signal.

said chemical to enter said chamber, said second valve means beingoperable in response to a pressure produced by said detonation toprevent the chemicals from entering said chamber; sensing meansproducing a feedback signal i upon the operation of saidsecond valvemeans; and

means combining an input signal and said yfeedback signal y so as toproduce said control signal.

9. A digital control system comprising: a detonation chamber; aplurality of passages each supplying a hypergolic chemical to saidchamber; control valve means plosi- -tioned within each of saidpassages, said controly valve `v means normally preventing said chemicalfrom entering said chamber, said control valve means allowing saidchemical to enter said chamber in response to a control s signal; checkvalve means positioned Within each of said passages, said check valvemeans normally vpermitting said chemical to enter said chamber,saidcheclc valve means operable in response to a pressure produced by' adetonation of the chemicals so as to prevent said chemicalA 7. A digitalreaction control system comprising: ardetonation chmber; a pluralityofpassages each supplying a hypergolic chemical to-said chamber; controlmeans positioned Within each of said passages, said control meanscomprising iirst valve means operable inresponse to a` control signal toallow the chemicals to, enter said chamber, and second. valve meansoperable in response to a pressure produced bya detonation ofsaidchemicals' Vto prevent said chemical from entering said chamber; sensingmeans producing a feedback signal indicative of the operation of saidsecond valve; and means combining an input vsignal and said feedbacksignal so as to produce said control signal. t L s 8.- A digitalreaction control system comprising:` adeto- `nation chamber; a pluralityof passages each supplying a hypergolic chemical to saidchamber, adetonation occurfrom entering `said chamber; sensing mean-s producing -afeedback signal upon the detonation ofthe chemicals; and means combining4an input signal and said feedback signal so asv to produce said controlsignal.

10. A digital control system comprising: :a detonation chamber; aplurality of passages each supplying a hypergolic chemical -to saidchamber; first valve means positioned within each of said passages, saidfirstvalve means Y normally being closed, said rst valve means beingopened VWithin each of said passages, said second valve means ringuponthe mixing of thechemicals Within said cham-V ber; control meanspositioned Within each of sai-d passages, sai-d control means comprisinga first valve means normallypreventing said chemical from entering saidY i chamber, said iirst valve means being operable in response f to`a"c`ontrol Vsignal solas tolallowsaid'chemical to enter said chamber,and secondval-ve means normally allowing inresponse to a control signaland allowing said chemical to enter said chamber; seoondrvalve meanspositioned norm-ally being open, said second-Valve means being closed inresponse to a pressure produced by a detonation of the chemicalsythereby preventing the chemicals from entering said chamber; sensingmeans producing -a feedback signal upon the closing of said secondvalve; and means combining an input signal and said feedback signal soas to produce said control signal.y

References Cited in the le of this patent UNITED STATES PATENTS2,743,577 `Malick May 1, 1956 2,930,526 Hendrickson v Mar. 29,1960

2,995,008 Fox ..fl. Aug. 8, 1961 u

7. A DIGITAL REACTION CONTROL SYSTEM COMPRISING: A DETONATION CHAMBER; APLURALITY OF PASSAGES EACH SUPPLYING A HYPERGOLIC CHEMICAL TO SAIDCHAMBER; CONTROL MEANS POSITIONED WITHIN EACH OF SAID PASSAGES, SAIDCONTROL MEANS COMPRISING FIRST VALVE MEANS OPERABLE IN RESPONSE TO ACONTROL SIGNAL TO ALLOW THE CHEMICALS TO ENTER SAID CHAMBER, AND SECONDVALVE MEANS OPERABLE IN RESPONSE TO A PRESSURE PRODUCED BY A DETONATIONOF SAID CHEMICALS TO PREVENT SAID CHEMICAL FROM ENTERING SAID CHAMBER;SENSING MEANS PRODUCING A FEEDBACK SIGNAL INDICATIVE OF THE OPERATION OFSAID SECOND VALVE; AND MEANS COMBINING AN INPUT SIGNAL AND SAID FEEDBACKSIGNAL SO AS TO PRODUCE SAID CONTROL SIGNAL.